I love the gargoyles. I'm guessing somebody added these at some point, probably their band logo or something. The grill cloth looks like it's been replaced...Sunn would have (should have) gotten the weave straighter, and it looks like there is some slack at the edges. No prob, still cool. From your description of the sound, it's possible the coil wire may have come partially loose from the coil form, but is still conducting. It's kind of a fuzzy metallic rattle. Unfortunately, no easy fix that I know of. Recone or replacement. BEFORE you do that though, take the speaker out and make sure the dust cap hasn't just come loose. From the picture, it looks like it's an aluminum cap. Yep, sound awful if they come loose. If so, just carefully glue it back down, I recommend a very thin bead of epoxy. DON'T allow the glue to run down into the gap...speaker death. Good luck !